<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>jQuery对象</title>
  <script src="./libs/jquery-3.2.1.min.js"></script>
  <script>
	$(document).ready(function(){
		var $foo = $("#foo");
		$foo.html("Foo jQuery");
		
		var $items = $("p");
		console.log($items.length);
		$items.html($items.html() + " jQuery");
	});
  </script>
</head>
<body>
	<h2>jQuery对象</h2>
	<p id="foo">Foo</p>
    <p id="bar">Bar</p>
</body>
</html>